#include<bits/stdc++.h>
//#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math")
//#pragma GCC optimize(2)
//#pragma GCC optimize(3)
//#pragma GCC optimize("Ofast,unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4.1,sse4.2,avx,avx2,popcnt,tune=native")
//#include <immintrin.h>
//#include <emmintrin.h>
#define int long long
#define ls(x) ((x)*2)
#define rs(x) ((x)*2+1)
#define fi first
#define se second
#define pii pair<int,int>
#define Debug(...) fprintf(stderr, __VA_ARGS__)
#define For(i,a,b) for(int i=a,i##end=b;i<=i##end;i++)
#define Rof(i,a,b) for(int i=a,i##end=b;i>=i##end;i--)
#define rep(i,  b) for(int i=1,i##end=b;i<=i##end;i++)
using namespace std;
const int N=1e6+5,base=999983,Mod=998244353;
//char buf[(1<<21)+5],*p1,*p2;
//#define getchar() (p1==p2&&(p2=(p1=buf)+fread(buf,1,1<<21,stdin),p1==p2)?EOF:*p1++)
inline void chmx(int &x,int y){(x<y)&&(x=y);}
inline void chmn(int &x,int y){(x>y)&&(x=y);}
inline void Add(int &x,int y){(x=x+y+Mod)%=Mod;}
inline int read(){
	int f=0,x=0;
	char ch=getchar();
	while(!isdigit(ch)){f|=(ch=='-');ch=getchar();}
	while(isdigit(ch)){x=(x<<3)+(x<<1)+(ch^48);ch=getchar();}
	return f?-x:x;
}
void print(int n){
    if(n<0){
        putchar('-');
        n*=-1;
    }
    if(n>9) print(n/10);
    putchar(n%10+'0');
}
int n;
int a[N],b[N],in[N]; 
vector<int>q[N];
signed main(){
	freopen("pairint.in","r",stdin);
	freopen("pairint.out","w",stdout);
	// ios::sync_with_stdio(false);
	// cin.tie(0); cout.tie(0);
	n=read();
	For(i,1,n) a[i]=read(),b[i]=read(),q[a[i]].push_back(b[i]),q[b[i]].push_back(a[i]),in[a[i]]++,in[b[i]]++;
	n*=2;
	queue<int>Q;int ans=0;
	For(i,1,n)if(in[i]==1){
		Q.push(i);
	}
	while(!Q.empty()){
		int x=Q.front();Q.pop();
		if(in[x]!=1) continue;
		ans++; 
		for(auto y:q[x]){
			in[y]--;
			if(in[y]==1) Q.push(y);
		}
	}
	For(i,1,n)if(in[i]>1)ans++;
	printf("%lld\n",ans); 
#ifdef LOCAL
    Debug("\nMy Time: %.3lfms\n", (double)clock() / CLOCKS_PER_SEC);
#endif
	return 0;
}

